Toboggan with runners

ABSTRACT

The toboggan proposed has a device which adjusts the runner to allow the toboggan to negotiate curves, the adjustment being made by means of a steering member in such a way that the radius of curvature of the runners is the same as the radius of the curve to be negotiated. The toboggan may be stopped by an automatic braking member when the steering member is not pulled rearwardly or restrained by the operator of the toboggan.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a sled with runners. Sleds are used forsliding on low-friction ground, particularly on a blanket of firm snow.To steer the prior art sleds, the driver forces his or her shoe or bootagainst the runway for the sled so as to brake the sled and to pull ittoward the side on which it is braked.

2. Description of the Prior Art

Sleds are known having runners which are divided in the longitudinaldirection and in which the front pair of runners can be pivotally movedlaterally outwardly by steering means. In that case the sled will travelin the direction in which the leading ends of the pair of runners whichhave been deflected are directed.

SUMMARY OF THE INVENTION

The known modes of steering have the disadvantage that kinetic energy ofthe sled will be dissipated for steering so that the velocity of thesled will be decreased although this is not intended. With pivotedrunner sections the energy loss is caused by the lateral slipping of thepair of trailing runners.

It is an object of the invention to provide a sled which can be steeredalmost without a loss of kinetic energy.

As a result of the deformation of the runners for cornering, the entiresliding surface of the sled is approximately adapted to the radius ofthe corner to be turned. The adaptation is almost perfect when eachrunner is pivoted at its front or rear end to the body of the sled, oneof the hinges of each of the two sets of hinges is slidable along therunner, and the force for bending each runner acts on the runnerapproximately at its center at right angles to the direction of traveland parallel to the surface of the runway for the sled. Because thedeflection of the resilient runners consists of an elastic deformationover a distance which is small relative to the length of the runner,that deflection will be in first approximation a circular deformation sothat it will ideally correspond to the radius of the corner to beturned.

If the runners are of a sufficient length, they may be mounted in thehinges to be non-displaceable in the longitudinal direction. In thatcase, the lateral bending of the runner will no longer be ideal for thegeneration of the radius of the corner but will still be sufficient forsteering the sled with a low loss of kinetic energy.

The deflection of the runners is preferably effected with a pivotedlever. The lever, which protrudes over the top surface of the sled, canbe conveniently actuated. In a preferred embodiment, the pivotable leveris coupled to a spring-biased braking means so that the release of thepivotable lever will cause a braking member between the runners to beforced down against the snow to effect an automatic braking. Thepivotable lever, due to it projecting vertically upward acts as afurther automatic braking element on the snow surface when the sledturns over.

BRIEF DESCRIPTION OF THE DRAWINGS

An example of the sled in accordance with the invention will now beexplained in more detail with reference to the drawings.

FIG. 1 is a functional representation of the operation by which the sledis steered;

FIG. 2 is a longitudinal sectional view showing the sled; and

FIG. 3 is a front elevation showing the sled viewed in the directiondesignated III in FIG. 2 with the runners of the sled shown in section.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates the operation by which a sled 1 is steered whichcomprises laterally disposed left-hand and right-hand resilient runners3a and 3b. A pivotable lever 5 is provided in the forward portion of thesled 1 and protrudes over the seat 16 of the sled. The pivotable lever 5exerts, by means of a force-transmitting unit shown in FIGS. 2 and 3, aforce 7a and 7b, at right angles to the direction of travel 6 of thesled and parallel to the plane in which the runners 3a and 3b aresliding on the runners hinges 9a/9b and 10a/10b mounted on the body of13 of the sled. In FIG. 1 the extent to which the runners 3a and 3b canbe laterally deflected is greatly exaggerated. Because the actuallateral deflection of the runners during a cornering of the sled issmall relative to the length of the runner between the two hinges 9a/9band 10a/10b, the runners will be deflected in circular shape inaccordance with the radius of the corner to be turned.

The pivotable lever 5 is pivoted by means of a flange 12 which acts as alever arm. The flage 12 is attached to a hinge 15 which is provided atthe end of a shaft 14. The shaft 14 is parallel to the longitudinal axisof the sled 1 and mounted to extend below the seat 16 of the sled. Thepivotable lever 5 is pivotally movable in a direction which is parallelto the longitudinal axis of the sled. To turn the shaft 14, thepivotable lever 5 is pivotally moved to the left or right with respectto the longitudinal axis of the sled or perpendicular to thelongitudinal axis of the sled. The shaft 14 is mounted on the body 13 ofthe sled by two bearings 17a and 17b. As shown in FIG. 3, a shapedmember 19 having an aperture 18, is fixedly connected to and protrudesfrom the rear portion of the shaft 14. The shaped member 19 isresiliently clamped without a backlash in a U-shaped holder 21. TheU-shaped holder 21, is connected to a linkage 23 which serves totransmit the force 7a and 7b for bending the runners and centrallyengages the runners 3a and 3b. As a result, the deflecting forces 7a and7b are transmitted from the pivotable lever 5 via the flange 12 and thehinge 15 as a rotary movement to the shaft 14 and from the shaft 14 viathe shaped member 19, the U-shaped holder 21 and the linkage 23 to themiddle of the runners 3a and 3b.

The hinge 15 is designed so that a pivotal movement 22 imparted to thepivotable lever 5 for steering the sled 1 will be converted with thesmallest possible backlash to a rotary movement of the shaft 14. Thepivotal movement of the shaped member 19 that is rigidly connected tothe shaft 14 is transmitted to the U-shaped holder 21 owing to the shapeof the shaped member 19. The mutually opposite curved portions 28a and28b of the shaped member 19 lie against the legs of the holder 21 duringthe steering operation and are spaced the same distance apart throughoutthe pivotal movement because they constitute segments of a circle.Backlash is eliminated because the curved portions 28a and 28b of theshaped member 19 are resiliently clamped between the legs of theU-shaped holder 21. The elastic "clamping force" of the legs is so thecurved portions 28a and 28b are resiliently pivotally movable within theholder 21 and due to uneven portions of the runway and are transmittedvia the runners 3a and 3b and the linkage 23 to the holder 21 will notcause a gap to be formed between the shaped member 19 and the holder 21.The effects of jerks on selected that the clamped but are jerks whichare the steering without a backlash are further reduced because thelinkage comprises a bend 23a, which interconnects the linkage arms 23band 23c which engage the runners 3a and 3b.

The portion of the pivotable lever 5 disposed below the seat 16 of thesled is spaced from the shaft 14 so as to act as a lever arm. A rod 25is mounted on the pivotable lever 5 by a hinge 27 so that a forward andrearward pivotal movement 24 of the free end of the pivotable lever 5will impart a linear forward and rearward movement to the rod 25. Theother end of the rod 25 is mounted by means of a hinge 26 toapproximately in the middle of a brake flap 29. The brake flap 29 ispivoted by a hinge 30 near the bearing 17b to be pivotally movable atright angles to the longitudinal axis of the sled. A tension spring 31is fitted on the end of the rod 25 adjacent to the hinge 26. The otherend of the tension spring 31 is secured to a flange 33, which is fixedlyjoined to the underside of the seat 16.

When the end of the pivoted lever is pulled back, the rod 25 will bepushed forward and the brake flap will be pivoted downward and forcedagainst the runway 35 so as to brake the moving sled. When the pivotablelever 5 is not urged forward but unrestrained, the spring 31 for thatpurpose will automatically pull the brake flap 29 against the flange 33in order to force the brake flap 29 down against the runway 35 for thesled and to pull back the pivoted lever 5 to an approximately verticalposition. When unrestrained, the pivotable lever 5 will always return toa vertical position and force the brake flap 29 downward.

As is apparent from FIG. 3 the seat 16 is semicircular in cross-sectionin order to provide convenient and safe seating on the sled.

The brake flap 29 is pivotally movable only at right angles to thelongitudinal axis of the sled. Although the brake flap 29 is connectedto the pivotable lever 5, it does not move in unison with the pivotablelever 5 during a lateral pivotal movement 22. During a steeringoperation, the brake flap 29 will always remain in position so that itcan brake with optimum effect. The slight twisting between the hinge 23,which due to the action of pivotable lever 5 is pivotally movable atright angles to the longitudinal axis of the sled, and the brake flap29, which is pivotally movable only in the direction of travel, will beallowed by the rod 25 and the backlast in the bearings 26 and 27.

To permit reliable transportation of the sled 1 for example, on the roofof a car, the pivotable lever 5 can be pushed forward to lie on the topof the seat 16. In that case the brake flap 29 will lie against theunderside of the seat 16 of the sled. Because the pivotable lever 5 canbe pivotally moved as far as to the seat 16 of the sled, the driver ofthe sled 1 can "fall over" the seat of the sled for example, when thesled 1 is caught by an earth mound.

In other embodiments, the pivotable lever 5 may be replaced by differentmeans, such as, for example, steering wheels, which may be circular orsemi-circular or have different shapes, or pedals provided withdeflected ropes for actuation by the feet.

I claim:
 1. A steerable sled comprising a plurality of runners which aredeformable by an adjusting means for steering the sled;a user actuatedsteering member which acts on the adjusting means; an automatic brakingmeans which includes a braking member operatively connected to thesteering member, the braking member being normally biased downwardlyinto a braking position for engagement with a runway for the sled andthe braking member being movable to a raised non-braking position whenthe steering member is pulled by the user; said adjusting meanscomprising a shaft upon which the steering member is mounted, lateralpivotal movement of the steering member by the user resulting in arotary movement of the shaft, the shaft extending in the longitudinaldirection of the sled and to which a first force-transmitting means isrigidly connected, which by means of a second force transmitting means,effects the lateral deformation of the two runners; said secondforce-transmitting means further including a force-transmitting linkagewhich is connected to the runners and a resilient clamp by which thefirst force-transmitting means are resiliently clamped in such a mannerthat the first force-transmitting means can rotate in the clamp and willconvert a rotary movement of the shaft to a linear movement of theforce-transmitting linkage.
 2. The sled of claim 1, further comprising:afront and a rear portion of a body of the sled to which the runners aremounted on both sides of the sled; a front and a rear hinge of eachrunner upon which the adjusting means laterally acts in such a mannerthat in dependence on the desired steering direction the runners areresiliently curved to one side or the other and the radius of curvatureof the runners is adjustable to correspond to the radius of the cornerto be turned by the sled in order to reduce the loss of kinetic energy.3. The sled of claim 1, wherein the steering member, further comprises apivoted lever which is connected to the adjusting means and is pivotallymovable laterally with respect to the longitudinal axis of the sled tocause the runners to be deformed by the adjusting means.
 4. The sled ofclaim 1, further comprising a force-transmitting means upon which thesteering member acts for actuating the braking member.
 5. The sled ofclaim 4, wherein the steering member further comprises a pivoted leverand a lever arm located at a distance from a hinge connecting thepivoted steering member to the shaft for exerting a force on the meansfor transmitting force to the braking member.
 6. The sled of claim 1wherein the steering member further comprises a pivotable lever mountedon the shaft, said lever being movable in the longitudinal direction ofthe sled between a non-braking position and a position in which thepivotable lever preferably completely rests on a seat of the sled.